Preparation of granular polymer



Patented June 13, 1950 UNITED STATES PATENT OFFICE PREPARATION OF GBANULAR POLYMER- IZATION PRODUCTS No Drawing. Application December 0, 1947, Serial No. 700,222

16 Claims. (Cl. 260-23) This invention relates to vinyl halide-containing polymeric products. More particularly. this invention relates to vinyl halide-containing polymeric products in a finely divided state.

In my co-pending No. 691,412. filed August 17, 1046, now Patent Number 2,476,474. there is disclosed and claimed a process for the polymerization of vinyl halideoontaining materials in aqueous suspension. there being dissolved in the aqueous phase thereof an heteropolymer of vinyl acetate and maleic acid or anhydride. This process leads to granular products of high quality. However, considerable diillculty is encountered in obtaining the granular products with the degree of fineness sometimes desired.

It is an object oi this invention to provide vinyl halide-containing polymeric products in the term 01 fine grains. A particular object oi. this invention is to provide a method for reducing the particle size 01 the granular product obtained by polymerizing vinyl halide-containing materials in the presence oi an aqueous solution of an heteropolymer of vinyl acetate and maleic acid or anhydride.

These and other objects are accomplished according to this invention by polymerizing vinyl halide-containing materials in an aqueous suspension. the aqueous phase thereoi having dissolved therein an heteropolymer of vinyl acetate and maleic acid or anhydride, in the presence of patent application. Serial ii 2 as limitative thereof. Where parts are mentioned. they are by weight.

In each example in Table I. the procedure used is that given below.

200 parts or water are placed in a glass-lined autoclave and then the indicated amount of heteropolymer oi vinyl acetate and maleic anhydride is added and dissolved in the water by heating and stirring the mixture. Thereafter.

0.2 part of lauroyl peroxide and the glyceryl mono-octadecanoate are introduced and the air in the autoclave is swept out with vinyl chloride gas. The autoclave is then sealed and 100 parts of monomeric vinyl chloride are introduced. The

16 resulting mixture is heated and stirred at 50 C.

for hours. As a result 01' this treatment, substantially all oi the vinyl chloride is polymerized. i. e., more than 95%. The polymeric products which comprise powders possessing varying de- 20 grees of coarseness are recovered from the suspending medium by centrifuging the product. The recovered polymers are washed with water and dried.

The heteropolymer used in the examples is made by copolymerizing one gram molecular so being freed from the benzene by drying at -70 C., is in the form of a fine powder.

Table Screen Analnis oi the Product Hetero- Example polymer 151m 40-mem ll mseh -mesh (so-mesh Pam Ports Per cent Per cent Per cent Per cent 0. 4 l. 6 ii. I 41.8 40

0. 3 l. 5 6. 0 I4. 2 58 I 0. 2 0. 4 0.6 0 8. 8 00. 6 "V 0. 3 0. 4 0 0 8. 4 Ill. 6 I 0. 4 0. 4 0 0. 5 15. 0 B4. 6 V 0. 3 0. l 0. I 2. 4 8i. 4 06. 1 V1 0.8 0.2 0 0.4 19.0 80.6 V111 0.3 0.4 0 0.4 9.8 00.3 IX 0.3 0.8 0 0.8 3.7 00.0 X 0. 8 0. 4 0 0 l1 8 87. 5

a compound from the group consisting of unsaturated aliphatic acids having 10-20 carbon atoms, hydroxyl group-substituted aliphatic acids having 10-20 carbon atoms and partial esters or polyhydric alcohols and aliphatic acids. said acids having 10-20 carbon atoms.

The following examples are illustrative of the present invention. but are not to be construed It is apparent from consideration of the screen that the inclusion of glyceryl mono-octadecanoate in the polymerization charges has an unexpected and pronounced efi'ect on the particle size of the products. Other particle size-reducing agents oi the invention are also eflective in this respect.

more than is desirable since in some cases the effectiveness of the agent falls oil when large amounts are used. A preferred range of proportions is 005-211 of the agent based on the amount of the monomeric material.

Various unsaturated aliphatic acids containing -20 carbon atoms, hydroxy aliphatic acids containing 10-20 carbon atoms, and partial esters of polyhydric alcohols and aliphatic acids, the acid residues thereof containing 10-20 carbon atoms may be used in accordance with the invention.

Examples of hydroxy acids having 10-20 carbon atoms which may be used alone or in the form of partial esters as particle size reducing agents in accordance with the invention include both saturated and unsaturated hydroxy acids such as IZ-hydroxy-octadecanoic acid, 9,10-hydroxy-octadecanoic acid, 12-hydroxy-dodecanoic acid, lfi-hydroxy-hexadecanoic acid, ll-hydroxyhexadecanoic acid, 10 hydroxy-octadecanoic acid, 3,12-dihydroxy-palmitic acid, 9,10,16-hydroxy-hexadecanoic acid, 9,10,12,13-hydr0xycctadecanoic acid l6-hydroxy-'7-hexadecenoic acid, i2-hydroxy-9-octadecenoic acid.

Examples of unsaturated aliphatic acids which may be employed. alone or in the form of partial esters are mono-oieflnic unsaturated aliphatic acids, such as 'l-hexadecenoic acid, 'lO-undecenoic acid, 'l3-docosenolc acid and 9-octadecen0ic acid; dioleflnic-unsaturated aliphatic acids such as 9,12-octadecadienoic acid; triolefinic-unsaturated aliphatic acids such as 9,12,15-octadecatrienoic acid, 9,11,13-octadecatrienoic acid; substituted oleflnic acids, for example, such hydroxy cleflnic acids as IG-hydroxy-l-hexadecenoic acid and 12 hydroxy 9 octadecenoic acid; halogenated unsaturated acids. for example, monochloro-Q-octadecenoic acid, monochloro 12 hydroxy-9-octadecenoic acid and halogenated acids derived by dehydration of castor oil acids followed by chlorination; aeetylenic unsaturated aliphatic acids, such as 'l-hexadecynoic, il-octadecynoic and 13-docosynoic acids.

Among the polyhydric alcohols from which the partial esters may be made are glycerin, mannitol, sorbitol, glucose, erythritol, pentaerythritol. glycois such as ethylene glycol, propylene glycol, diethylene glycol. triethylene glycol, tetraethylene glycol, etc. Various saturated and unsaturated aliphatic acids may be reacted with the poiyhydric alcohols in making the partial esters. A preferred group of partial esters are those containing a single ester linkage. However. partial esters containing more than one ester linkage may be used.

The acids used in making the partial esters may be saturated or unsaturated aliphatic acids containing 10-20 carbon atoms. Examples of such acids include the unsaturated acids and hydroxy acids set forth above which are also effective in the unreacted state as particle size reducins agents.

Examples of saturated fatty acids other than those set forth above, which may be employed in preparing the partial esters are decanoic acid, undecanoic acid. dodecanoic acid, tridecanoic acid. tetraldecanoic acid. pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid and nonadecanoic acid. These acids may have straight or branched chains. or substituted chains, and may be substituted, for example, with chlorine or other halogen atoms. as for example, monochloroctadecanoic acid. and the like.

Specific partial esters coming within the scope of the invention include glyceryl mono-hexadecanoate, glyceryl mono-dodecanoate, glyceryl mono 9 octadecenoate, glyceryl mono-lz-hydroxy-octadecanoate, sorbitain monododecanoate polyoxy alkylene derivative, sorbitan mono-octadecanoate polyoxy alkylene derivative. propylene glycol mono octadecanoate, ethylene glycol mono-octadecanoate. diethylene glycol monooctadecanoate and sorbitan mono-octadecanoate. These and other particle size reducing agents of the invention may be substituted for the glyceryl mono-octadecanoate in the examples of Table I with generally similar results.

A preferred group of particle size reducing agents are those which are free from unsaturation, i. e., saturated hydroxy acids and partial esters of polyhydric alcohols with saturated acids such as those mentioned above.

The heteropolymers of vinylacetate and maleic acid or anhydride used in the process of the invention may be made by usual methods of producing such polymeric products. e. g., in solution,

in mass, or in a liquid which is a solvent for the monomeric materials, but not for the heteropolymer. Illustrative examples are set forth in my copending patent application. Ser. No. 691,412, filed August 17, 1946. A particularly preferred procedure is set forth in my co-pending application Serial No. 790,221, filed December 6, 1947, whereby especially high molecular weight products are obtained by polymerization in the presence of a small amount of a material which is a solvent for the monomeric materials, but not for the heteropolymer.

Usually maleic anhydride is preferred over maleic acid as the copolymerizing material in view of the faster polymerization rates which result and the greater solubility of the anhydride. Since on solution of the vinyl acetate-maleic anhydride heteropolymer in water, the anhydride groups hydrolyze to carboxyl groups, there is no disadvantage in using this heteropolymer.

In preparing the heteropolymers in the presence of a solvent for the monomers which is a non-solvent for the polymer. such liquids may be used as benzene. toluene, xylene, hexane, chlorobenzene. chlorotoluene, chloroxylene dichloroethylene, trichloroethylene and the corresponding bromo and fluoro compounds.

The heteropolymer containing suspending agents may be made by polymerizing mixtures of vinyl acetate and maleic acid or anhydride in varying molar ratios, e. g., from 1:9 to 9:1. Usually, it is preferred that the ratio of maleic acid or anhydride to vinyl acetate does not exceed '1: 1 since the use of an excess of maleic acid or anhydride may be undesirable in some cases. Howeve it may be desirable that the ratio of vinyl acetate to anhydride exceed 1:1. For example, the ratio may be as high as 9: 1. as pointed out above.

Heteropolymers of vinyl acetate and maleic acid or anhydride possess a substantial solubility in water without the use of compounds forming salts therewith. Usually the aqueous solutions thereof are clear. However. the products resulting from polymerizing mixtures of vinyl acetate and maleic acid or anhydride containing a substantial molar is excess of vinyl acetate. 1. e., more than 1.5-2.0

mois 01' vinyl acetate for every mol oi' maleic acid or anhydride, tend to form hazy aqueous solutions. While these heteropolymers may be used as suspending agents and are comprehended by the present invention, it is preferred to use the heteropolymers which iorm clear aqueous solutions without the addition of salt-iorming materials since these heteropolymers are more ellective as suspending agents.

In carrying out the process oi the invention, the polymerizing temperature may be substantiall varied, and the temperature employed is governed by the particular characteristics desired in the polymeric material and the nature oi the material being polymerized. In the case 01 vinyl halides and many mixtures of vinyl halides and materials copolymerizable therewith, temperatures of -i00 C. are usually employed. Usually. only a small concentration oi! the dispersing agent of the invention is necessary. l icr example, 0005-2096 and, more particularly, OBI-0.5% based on the amount of water used. is usually suitlcient. However, larger amounts may be employed when desired, for example, up to the limit of solubility of the heteropolymer in the water. The optimum quantity oi the dispersing agent depends upon a number of factors, for example, the ratio of water to monomer. Thus, as the waterzmonomer ratio is increased, the ratio oi suspending agent to water may be decreased. Another factor afl'ecting the amount of the suspending agent required is the rate at which the particular charge polymerizes. In general, the faster the rate of polymerization, the smaller is the amount of suspending agent required. Other factors ail'ectlng the optimum amount of suspending agent include the degree oi fineness desired in the polymeric product and the speed" of agitation.

In carrying out the polymerization process of the invention, it is generally preferred that a water:monomer weight ratio or at least 1:1 be used, but generally, the waterzmonomer ratio does not exceed 9:1. The dispersing agent concentrations mentioned above may be used within these limits of water:monomer ratios.

As indicated above, it is desirable in carrying out the polymerization process oi the invention to substantially free the atmosphere above the polymerizing mixture from oxygen by replacing the air prior to polymerization with carbon dioxide, vinyl chloride, nitrogen or other inert gas. This may be done by sweeping out the air with a stream of inert gas or by subjecting the polymerization charge to partial vacuum, thereby sweeping out the air with vapors from the charge.

The process of this invention is useful in the polymerization of vinyl halides, e. g., vinyl chloride, vinyl bromide, etc. and the copolymerization of vinyl halides with such copolymerizable waterinsoluble unsaturated compounds as vinyl esters of carboxylic acids, for example, vinyl acetate. vinyl propionate, vinyl butyrate, vinyl benzoate; esters of unsaturated acids, for example, methyl acrylate, ethyl acrylate, butyl acrylate, allyl acrylate and the corresponding esters of methacrylic acid; vinyl aromatic compounds, for example, styrene, ortho-chlorostyrene, para-chlorostyrene, 2,5-dichlorostyrene, 2.4-dichlcrostyrene, paraethyl styrene, divinyl benzene, vinyl naphthalene, alpha-methyl styrene; dienes such as butadiene, chloroprene; amides such as acrylic acid amide, acrylic acid anilide; nitriles, such as acrylic nitrile; esters of nip-unsaturated carboxylic acids. for example, the methyl, ethyl, propyl, butyl.

6 amyl, hexyl, heptyl, octyl, allyl, methallyl and phenyl esters oi maleic, crotonic, itaconio, iumaric acids and the like.

Preferably, in the case oi copolymerization, a predominant portion, 1. e., more than by weight, 01 the mixture of monomers is a vinyl halide, especially vinyl chloride.

A particularly preferred embodiment of the invention comprises the polymerization of a mixture of vinyl chloride and an ester of an a p-unsaturated dicarboxylic acid such as diethyl maleate, in which 5-20 parts by weight of the ester are used for every -80 parts by weight 01 vinyl chloride. Among the preferred esters of ll,fi-un" saturated dicarboxylic acids are the alkyl esters in which the alkyl group contains 2-8 carbon atoms.

In place of lauroyl peroxide used in the examples, other water-insoluble catalysts may be used such as benzoyl peroxide, ditertiary butyl peroxide, oleyl peroxide, toluyl peroxide and the like. Mixtures 0! two, three or more of these and other catalysts may be used when desired. In certain cases, the catalyst may be eliminated, for example, when rapid polymerization is obtained in the absence of catalyst. In certain cases, the action of light may be helpful in expediting the polymerization.

The above catalysts are also illustrative of catalysts which may be used in making the heteropolymer dispersing agent.

The foregoing description is given in illustration and not in limitation or the invention as set forth in the appended claims.

What is claimed is:

1. In a process wherein a polymerizable material containing a vinyl halide from the group consisting of vinyl chloride and vinyl bromide is polymerized while dispersed in an aqueous medium having dissolved therein as a dispersing agent a heteropolymer of vinyl acetate and a substance from the group consisting of maleic acid and maleic anhydride, the step which comprises incorporating in the aqueous medium prior to polymerization=ll.0l% to 5%, based on the monomeric materials, of a particle size reducing agent from the group consisting of unsubstituted unsaturated aliphatic carboxylic acids having from 10 to 20 carbon atoms, hydroxyl group-substituted aliphatic carboxylic acids containing from 10 to 20 carbon atoms, halogen substituted unsaturated aliphatic earboxylic acids having from 10 to 20 carbon atoms and partial esters of polyhydric alcohols and aliphatic carboxylic acids, said alcohols having from 2 to 8 carbon atoms and said acids having from 10 to 20 carbon atoms.

2. A process as defined in claim 1 in which the polymerizable material is vinyl chloride.

3. A process as defined in claim 1 in which the aqueous dispersion contains a mixture of vinyl chloride and an unsaturated compound copolymerizable therewith.

4. A process as defined in claim 3 in which the copolymerizable compound is a vinyl ester of a lower aliphatic acid, said acid having from 2 to 4 carbon atoms.

5. A process as defined in claim 4 in which the vinyl ester is vinyl acetate.

6. A process as defined in claim 1 in which the particle size reducing agent is a hydroxyl groupsubstituted aliphatic carboxylic acid.

'7, A process as defined in claim 6 in which the acid is a saturated acid.

8. A process as defined in claim 1 in which the 7 particle size reducing agent is an unsubstituted unsaturated aliphatic carboxyiic acid.

9. Aprocessasdefinedlnclaim l in'whichthe particle size reducing agent is a partial ester of a polyhydrlc alcohol and an aliphatic carboxyiic vacid, said alcohol having from 2 to 8 carbon agms and said acid having irom 10 to 20 carbon 9. ms.

10. A process as defined in claim 9 in which the partial ester is a glyceryl partial ester.

11. A as defined in claim 10 in which the partial ester is glyceryl monostearate.

12. A process as defined in claim 11 in which the vinyl halide is vinyl chloride.

l3.-A process as defined in claim 1 in which No references cited.

Certificate of Correction Patent No. 2,511,811

June 13, 1950 MASSIMO BAER It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 73, after the word acry1ic", second occurrence, insert acid; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of September, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommiuionot of Patents.

7 particle size reducing agent is an unsubstituted unsaturated aliphatic carboxyiic acid.

9. Aprocessasdefinedlnclaim l in'whichthe particle size reducing agent is a partial ester of a polyhydrlc alcohol and an aliphatic carboxyiic vacid, said alcohol having from 2 to 8 carbon agms and said acid having irom 10 to 20 carbon 9. ms.

10. A process as defined in claim 9 in which the partial ester is a glyceryl partial ester.

11. A as defined in claim 10 in which the partial ester is glyceryl monostearate.

12. A process as defined in claim 11 in which the vinyl halide is vinyl chloride.

l3.-A process as defined in claim 1 in which No references cited.

Certificate of Correction Patent No. 2,511,811

June 13, 1950 MASSIMO BAER It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 73, after the word acry1ic", second occurrence, insert acid; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of September, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommiuionot of Patents.

Certificate of Correction Patent No. 2,511,811 June 13, 1950 MASSIMO BAER It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 73, after the word acrylic, second occurrence, insert acid;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of September, A. D. 1950.

THOMAS F. MURPHY,

Am'atant Commissioner of Patents. 

1. IN A PROCESS WHEREIN A POLYMERIZABLE MATERIAL CONTAINING A VINYL HALIDE FROM THE GROUP CONSISTING OF VINYL CHLORIDE AND VINYL BROMIDE IS POLYMERIZED WHILE DISPERSED IN AN AQUEOUS MEDIUM HAVING DISSOLVED THEREIN AS A DISPERSING AGENT A HETEROPOLYMER OF VINYL ACETATE AND A SUBSTANCE FROM THE GROUP CONSISTING OF MALERIC ACID AND MALEIC ANHYDRIDE, THE STEP WHICH COMPRISES INCORPORATING IN THE AQUEOUS MEDIUM PRIOR TO POLYMERIZATION 0.01% TO 5%, BASED ON THE MONOMERIC MATERIALS, OF A PARTICLE SIZE REDUCING AGENT FROM THE GROUP CONSISTING OF UNSUBSTITUTED UNSATURATED ALIPHATIC CARBOXYLIC ACIDS HAVING FROM 10 TO 20 CARBON ATOMS, HYDROXYL GROUP-SUBSTITUTED ALIPHATIC CARBOXYLIC ACIDS CONTAINING FROM 10 TO 20 CARBON ATOMS, HALOGEN SUBSTITUTED UNSATURATED ALIPHATIC CARBOXYLIC ACIDS HAVING FROM 10 TO 20 CARBON ATOMS AND PARTIAL ESTERS OF POLYHDRIC ALCOHOLS AND ALIPHATIC CARBOXYLIC ACIDS, SAID ALCOHOLS HAVING FROM 2 TO 8 CARBON ATOMS AND SAID ACIDS HAVING FROM 10 TO 20 CARBON ATOMS. 